When producing synthetic fibers or filaments and particularly synthetic continuous filaments usable as textiles from heat softened mineral material, such as molten glass or the like, it is conventional practice to use a stream feeder or bushing. Such feeders are normally made of platinum alloy and have a bottom wall with a plurality of orificed projections through which pass streams of heat softened mineral material. Suitable apparatus attenuates the streams into continuous fibers or filaments.
Stream feeders have been produced by a number of methods in the past. One method has been used to use a punching operation. In this method a plate having a slightly oversized thickness is stamped by a blister die. The blister die has a series of projections corresponding to the number and pattern of the desired orificed projections in the final stream feeder. The stamping of the plate by the blister die forms a plurality of raised portions on one side of the plate. The plurality of raised portions thus becomes the pattern for further production of the orificed projections in the plate. A punch press operator uses these raised portions as a guide when he carries out the punching operations to form orificed projections at each of the raised areas.
The deficiencies of the prior art stream feeder fabrication method as described above become more acute under modern filament-forming conditions. This method is very operator-dependent. This can be a problem as bushings today often have increased numbers of orificed projections, such as 2,000 or more. Also, there is a difficulty with this method in producing stream feeders which have a relatively high orifice density, as the plate elongates during punching. As the plate elongates, an operator can have difficulty properly aligning the plate within the punching press, which can result in defective base plates. Another difficulty with the blister die method of forming stream feeders is that an entirely new blister die must be produced for every desired base plate which has a different number of orificed projections or which has a different pattern of orificed projections.